Hydraulic turntable

ABSTRACT

A hydraulically-powered turntable including a fixed multiple channel oil feed mounting spool which functions as an axle for a rotary spool housing, the latter serving both as a turntable hub and a manifold for distributing oil in the performance of various hydraulic functions which are associated with the turntable as a whole. A worm drive for the turntable hub embodies a spring helix and worm wheel which, together with certain hub-stabilizing devices, operate in a pool of lubricating oil.

United States Patent 1191 Spellman, Jr. July 3, 1973 [54] HYDRAULIC TURNTABLE 1,289,427 12/1918 Ferris 212/69 3,049,936 8/ I962 Schnell 74/425 X [751 'F SWIM", Blue 2,126,404 8/1938 McLean 212/66 x s 3,268,268 8/1966 Schwalm 74/425 x [73] Assignee: Symons Corporation, Des Plaines,

lll. Primary Examiner-J. Franklin Foss Attorney-Norman l-il. Gerlach [22] Filed: Sept. 20, 1971 [21] App]. No.: 182,048 [57] ABSTRACT A hydraulically-powered turntable including a fixed 52 us. (:1 248/2, 74/425, 212/55, multiple channel feed mounting spool whh=h func- 212 tions as an axle for a rotary spool housing, the latter. 51 Int. c1. B66c 23/84 serving both as a turntable hub and a manifold for [58] Field 61 Search 248/2, 23; 212/55, tributing oil in the Performance of various hydraulic 212/65, 9; 7 425; 173 43; 1 2 2 functions which are associated with the turntable as a whole. A worm drive for the turntable hub embodies a 5 References Cited spring helix and worm wheel which, together with cer- UNITED STATES PATENTS tain hub-stabilizing devices, operate in a pool of lubrit I 3,424,318 1/1969 Lorence 212/69 ca mg on 3,543,944 12/1970 Woodside 212/66 2 Claims, 8 Drawing Figures Patented July 3, 1973 3,748,223

3 Sheets-Sheet 1 I N VE N TOR FRANCIS T." SPELLMAM QR Patented July 3, 1973 3,743,223

3 Sheets-Sheet 3 FIG. 5

N VE N TOR FRANCIS T.' SPELLMAN, JR.

Airy.

By; WWI/5 Patented July 3, 1973 3 Sheets-Sheet 5 l J E INVENTOR FRANCIS T SPELLMAN, JR.

HYDRAULIC TURNTABLE The improved hydraulically-powered turntable comprising the present invention is designed primarily for use as a conveyor mounting on a portable or mobile concrete pouring and spreading truck regardless of whether the latter be of the concrete mixing type or otherwise.

Heretofore, in connection with the conveyor tumtable mounting of a mobile unit which has concrete placement and spreading facilities and in which several hydraulic motors are employed for performing such functions as driving the conveyor belt and extending and contracting the telescopic conveyor sections, the flexible fluid lines leading to such motors have presented a problem in that they tend to wrap around the turntable housing during turntable rotation, as well as to interfere with one another and thus become entangled. This has limited turntable rotation to something less than 360. The present turntable is designed to obviate the above-noted limitation that is attendant upon the construction and use of a conventional or presentday conveyor turntable in that it affords a novel conveyor turntable assembly wherein fluid distribution to the various hydraulic units which are associated with the conveyor is effected by utilizing a central mounting spool which functions as an axle for a surrounding spool hub or housing, the spool defining a number of individual annular fluid channels and the spool housing functioning in the manner of a rotatable manifold which is provided with outlet ports that register with the channels in all positions of the spool housing and which are connected by fluid lines to the various hydraulic motors which are utilized in connection with the associated conveyor. By such an arrangement, the circumferential positions of the hydraulic motors do not vary with respect to the circumferential positions of the outlet ports and, therefore, as the spool housing and conveyor rotate in either a clockwise or counterclockwise direction, the fluid lines which extend between the fluid ports in the spool housing and their respective hydraulic motors remain in the same radial plane, or substantially so, during housing rotation with the result that there will be no wrapping of the fluid lines about the spool housing or physical interference between such fluid lines.

A further feature of the present turntable resides in the provision of a worm drive for the rotatable spool housing, the drive embodying a relatively heavy-duty rotatable spring-like helix which has its opposite ends journaled in bearings on the turntable base and its medial region meshing in worm drive fashion with a worm wheel on the spool housing. The helix being resilient is capable of yielding slightly in the direction of drive, i.e., in the longitudinal or axial direction of the helix, so that as the helix is rotated for worm wheel driving purposes in either direction, the individual convolutions of the helix are forced deep into the trough regions between adjacent teeth of the worm wheel, thereby effecting a more positive worm drive than is the case with a conventional solid worm drive and, what is equally important, affording a shock-absorbing function during starting up and stopping operations by reason of the ability of the helix to absorb either the static drag or the kinetic overrun of the conveyor. By the same token, sudden conveyor shocks during turntable rotation are minimized or dampened.

An important feature of the invention resides in the provision of a novel submerged lubrication system for the worm drive mechanism whereby the worm-forming helix operates in a pool or body of lubricating oil so that maintenance costs are reduced to a minimum.

The hydraulically-powered turntable of the present invention is not necessarily limited to use in connection with a mobile concrete pouring and spreading trucl t, and a turntable embodying the principles of the present invention may, if desired and with or without modification as required, be employed with a wide variety of hydraulically-operable conveyors whether vehicle mounted or otherwise as, for example, a sand-carrying conveyor such as is employed in either a steel mill or a foundry installation for various uses. It also may be employed with a farm implement such as a manure spreader, or with a directional conveyor whatever be its function. The invention, in fact, is not necessarily limited to a turntable for a conveyor, and the present spool and housing assembly is capable of use with a wide variety of turntable assemblies of the type where a rotating turntable platform serves to support a plurality of hydraulically-operated units. regardless of whether the same be motors or other hydraulic devices, and where it is necessary to feed hydraulic fluid to such units from a common sump or other source. Irrespective, however, of the particular use to which the invention may be put, the essential features thereof are at all times preserved.

The provision of an hydraulic turntable such as has briefly been outlined above, and possessing the stated advantages, constitutes the principal object of the present invention. Other objects and advantages not at this time enumerated will readily suggest themselves as the nature of the invention is better understood from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter described and are more particularly defined by the claims at the conclusion hereof.

In the accompanying three sheets of drawings forming a part of this specification, one illustrative embodiment of the invention is shown.

In these drawings:

FIG. 1 is a vertical sectional view taken substantially centrally and vertically through a turntable assembly embodying the principles of the present invention;

FIG. 2 is a horizontal sectional view taken on the line 2-2 of FIG. 1 and in the direction of the arrows;

FIG. 3 is a bottom view of the turntable assembly;

FIG. 4 is a fragmentary vertical sectional view taken centrally through the proximate tail section of an exemplary truck-mounted, concrete-spreading conveyor with which the present turntable assembly is associated, the latter being shown in side elevation;

FIG. 5 is a horizontal sectional view taken on the line 5-5 of FIG. 4;

FIG. 6 is an enlarged sectional view taken on the line 6-6 of FIG. 5;

FIG. 7 is a vertical transverse sectional view taken on the line 7--7 of FIG. 6; and

FIG. 8 is an exemplary schematic hydraulic diagram showing the fluid lines leading to and from the various hydraulic componentsof a typical truck-mounted, concrete-spreading conveyor, the fluid being channeled by the present turntable assembly.

Referring now to the drawings in detail and in particular to FIGS. 1 to 3, inclusive, a turntable assembly embodying the present invention is designated in its entirety by the reference numeral 10 and, in FIGS. 4 and 8, the turntable assembly is shown as being operatively installed on the frame or chassis 12 of a concretespreading truck having associated therewith a directional, extensible and contractible conveyor 14. The function of the turntable assembly 10 is to provide a base mounting for the proximate tail section of the conveyor 14, as well as to supply hydraulic fluid to the various hydraulic operating components of the conveyor, such components consisting of a proximate hydraulic belt drive motor M1 (see FIGS. 4 and 8), a distal hydraulic belt drive motor M2, an hydraulic conveyor extension cylinder Cl, and an hydraulic conveyor lift cylinder C2. The rotatable turntable platform 20 (see FIG. 4') serves to support the proximate tail section 22 of the conveyor 14 and is adapted to be driven in either direction by a reversible worm drive mechanism which is designated in its entirety by the reference numeral 24 (see FIGS. 4 and and includes an hydraulic turntable drive motor M3, the latter being fixedly mounted on a frame extension 26 on the truck chassis 12. The worm drive mechanism 24 cooperates with a disk-like worm wheel 28 which is of relatively largediameter and on which the turntable platform 20 is mounted, the worm wheel deriving its support from the truck-chassis 12 in a manner that will be described in detail subsequently. Thw worm wheel 28 is provided on its central portion with a fixed tubular hub 30 which is supported rotatably on and encloses a fixed central vertical conveyor centering and supporting post 32 of spool-like design andfunctions as a central turntable axle. For convenience of description herein, this post 32 will hereinafter be referred to as a spool and the hub which is rotatably supported thereon will be referred to as the spool housing. The spool 32 and its surrounding spool housing 30 constitute, in effect, an oil distribution manifold from which branch fluid lines extend to the various hydraulic components in the form of the hydraulic motors M1 and M2, and the hydraulic cylinders C1 and C2, all in a manner that will be fully described presently when the details of the turntable assembly have been made clear.

Considering now the turntable assembly 10 in greater detail, the central supporting spool 32 is provided with a reduced lower end 34 (see FIG. 1) having a threaded section 36 which receives thereover a sleeve 38, the latter being locked in position on the threaded section of the reduced lower end of the spool by means of a set screw 40. The sleeve 38 is welded as indicated at 42 to a circular mounting plate 44 and the latter is secured by an annular series of nut and bolt assemblies 46 to a main imperforate turntable base plate 48, the latter constituting a part of the aforfementioned frame extension 26. The frame extension further includes a series of variously disposed transverse channel beams 50 (see FIG. 4) which are mounted on a longitudinally extending bottom channel beam 52.

As clearly shown in FIG. 1, the turntable spool housing 30 is rotatably supported on the turntable spool 32 by means of an upper and lower roller bearing assemblies 54 and 56. The inner race 58 of the lower bearing assembly 54 seats on the upper rim or end of the sleeve 38 while the outer race 60 of such bearing is nested within an internal annular recess 62 in the lower end of the spool housing 30, the sleeve 38 thus assimilating the downward thrust of the housing. The outer race 64 of the upper bearing assembly 54 is nested within an internal annular recess 66 in the upper end portion of the spool housing 30 and the upper end of the inner race 67 of such bearing bears against a horizontal plate 68 which is clamped in position by means of a nut and lock washer assembly 70.

The worm wheel 28 surrounds the spool housing 30 in the lower regions thereof and is welded thereto as indicated at 72. It is in the form of a horizontal, circular, large diameter plate having an annular series of teeth 74 cut in its periphery. Such teeth define therebetween substantially semi-cylindrical troughs 75. The central region of the worm wheel 28 is supported from the spool housing 30, while the peripheral region of the worm wheel is tractionally supported from the turntable base plate 48 by means of an annular series of circumferentially spaced, underlying traction rollers 76, the latter being rotatably mounted in composite brack ets 78 which are secured by bolt and nut assemblies 80 to the turntable base plate 48. Stabilizing rollers 82 overlie peripheral region of the worm wheel 28 and are also rotatably mounted in the brackets 78. The tumtable platform 20 is supported above the worm wheel 28 by means of a composite mounting ring spacer assembly 84 which is connected by bolts 86 to the worm wheel 28. The conveyor platform 20 has supported thereon a conveyor cradle frame 88 including a radially extending portion 90 to which the aforementioned conveyor lift cylinder C2 is pivoted as indicated at 91, and a vertical section 92 to which the proximate tail section 22 of the conveyor 14 is pivoted as indicated at 93. The conveyor 14 is of conventional construction and no claim is made herein to any novelty that may be associated therewith. Accordingly, the disclosure of such conveyor herein is entirely schematic in its representation, it being sufficient to point out that this conveyor is of the extensible telescopic type and includes, in addition to the tail section 22, a medial section 94 (see FIG. 8) and an outer head or distal section 96, these sections being telescopically disposed with respect to one another with their telescopic movement taking place under the control of the aforementioned conveyor extension cylinder C1. As shown in FIGS. 4 and 6 of the drawings, the conveyor 14 further includes the usual belt-driving tail pulley and head pulley 102, the former being carried on the inner tail section 22 and the latter being carried on the outer head section 96. An endless belt 104 passes over the two pulleys 100 and 102 and also passes over various intermediate shiftable rollers 106 as is well known in the art. The pulley 100 is adapted to be driven by the aforementioned hydraulic motor M1, while the pulley 102 is adapted to be driven by the hydraulic motor M2. Extension and contraction of the various conveyor sections 22, 94 and 96 is effected under the control of the extension cylinder Cl.

Referring now to FIGS. 4 and 5, the aforementioned worm drive mechanism 24 by means of which rotational movements in either direction are imparted to the worm wheel 28 involves in its general organization a spring worm assembly 110 (see FIG. 6) which is mounted on the turntable base plate 48 and includes a spring-like worm helix 112 which is formed of resilient spring steel stock and the central axis of which assumes a substantially tangential disposition with respect to the periphery of the worm gear 28. The helix convolutions are circular in cross section and have a diameter which is substantially equal to that of the various troughs 75 between the teeth 74 of the worm wheel so that intimate worm and worm wheel meshing is attained.

The opposite ends of the worm helix 112 are welded or otherwise secured to a pair of torque transmitting hubs 114 (see also FIGS. 6 and 7) and the latter are keyed as indicated at 116 on a horizontally extending worm drive shaft 118. The hubs 114 are rotatably mounted in bushings 119 in a pair of bearing supports 120 which are secured by nut and bolt assemblies 122 to the base plate 48. The hubs 114 are formed with annular radial flanges 123 in their medial regions and thrust bearings 124 are interposed between such flanges and the bearing supports 120.

The hydraulic motor M3 is bolted or otherwise fixedly secured to the upper face of the turntable base plate 48 and the drive shaft 118 is operatively connected to the driven shaft of the motor M3 in driven relationship by means of a pair of flexible couplings 132 and 134 (see FIG. 5) which are, themselves, coupled together by a stub shaft 136.

It is to be noted at this point that the teeth 74 on the worm wheel 24 are flame cut so that the interstices or troughs 75 between adjacent teeth are conformable in shape to the surface contour of the individual convolu tions of thw worm helix 112. By such an arrangement, a nearly perfect mating of the worm helix with the worm wheel teeth is effected and certain drive functions that will be described subsequently are attained.

In order further to enhance the drive characteristics of the worm drive mechanism 24, means are provided whereby this mechanism is submerged and operates within a pool or body of lubricating oil. Accordingly, a continuous annular oil retaining or confining wall 137 having a cover plate 138 therefor, projects upwardly from the periphery of the base plate 48 and is adapted to receive therein a pool of lubricating oil (not shown), the level of which is maintained at least slightly above the level of the worm wheel 28 as indicated by the dotted line 11 in order that the worm helix 112 and the rollers 76 and 82 will operate in a body of the lubricating oil.

It has been previously stated that the hydraulic components which are mounted on the conveyor 14 consist of the belt drive motors M1 and M2, the extension cylinder C1 and the lift cylinder C2. Motive fluid for these various hydraulic components are, according to the present invention, selectively supplied thereto by flexible fluid lines leading from the rotatable spool housing 30 in order that such fluid lines shall not be subjected to a wrapping action about the turntable axis and in order that relative motion thereof shall be kept to a minimum. Accordingly, and as best illustrated in FIGS. 1 and 3, the spool 32 is provided with a plurality of Iongitudinally extending passages, such passages being collectively designated by the reference numeral 139 and corresponding in number to the number of fluid lines which are required to serve the various hydraulic components of the conveyor 14. Accordingly, an outflow passage which is common to and serves both belt drive motors M1 and M2 is designated by the reference legend (m1, m2 out). A return passage (in 1, m2 in) is provided for these two motors. An outflow passage (cl out) and a return passage (c1 in) serve the conveyor extension cylinder C1. A single passage (c2) serves the lift cylinder C2.

Each of the various passages 139 set forth above communicates with a respective annular groove which is provided in the cylindrical side surface of the spool 32, the various grooves being collectively designated by the reference numeral 140 and adjacent grooves being sealed from each other by flexible lip-type sealing rings 141. Each groove is maintained in constant register or communication with a screw-threaded fluid port 142 which is provided in the cylindrical wall of the spool housing 30 and these ports 142 communicate through respective flexible fluid lines or conduits 143 (see FIGS. 8) with the various hydraulic components of the conveyor 14. These fluid lines are designated or identifled by the legends (ml', m2 out), (ml', m2 in), (cl out), (c1' in) and (c2') in conformity with the previous legending.

As shown in FIG. 8, the truck on which the turntable 10 and the conveyor 14 are mounted may be provided with a suitable control panel 144 on which there are mounted control valves for regulating the flow of fluid to and from the various hydraulic components of the conveyor 14. Exemplary of such valves is a directional valve V1 having a sump connection, the valve being operatively connected to the fluid passages (ml, m2, in) and (m1, m2, out), a directional valve V2 operatively connected to the fluid passages (c1 in) and (c1 out), a directional valve V3 operatively connected to the fluid passage C2, and a directional valve V4 operatively connected to the turntable drive motor M3. The passages by means of which the valves V1, V2 and V3 are connected to the passages 139 are collectively designated by the reference numeral 146. All of the valves V1, V2, V3 and V4 are connected by a common inflow line to the outlet side of a pump P which is mounted on a convenient portion of the frame extension 26, the inlet side of the pump being connected by a line 152 to a sump S. An outflow line 154 extends between the sump S and the various valves.

From the above description, it is believed that the operation of the present hydraulically-powered turntable will be apparent without necessitating a detailed description thereof. It will be appreciated that all of the valves V1, V2, V3 and V4 are simple directional valves and that by manipulating the valve V1, hydraulic fluid will be directed through the internal passage (m1, m2 in) in the spool 32 from whence it will enter the associated groove 140 and then flow through the external fluid line (ml', m2 in) to both the tail motor M1 and the head motor M2, thus driving the conveyor belt 104. Fluid returns from the motors M1 and M2 through the external fluid line (ml', m2 out), the associated groove 140, and the internal passage (m1, m2 out) back through the valve V1 to the sump S. A similar hydraulic circuit involving the passages (c1 in) and (c1 out) and their associated respective fluid lines (cl' in) and (c1' out) is associated with the directional valve V2 for effecting extension and retraction of the conveyor 14. A third hydraulic circuit involving the passages (m3 in) and (m3' out) is associated with the directional valve V4 for controlling the hydraulic motor M3.

It is to be noted that only one passage (c2) and connecting outflow fluid line (c2') extend from the valve V3 to the lift cylinder C2. This passage and line are used for both outflow and inflow purposes inasmuch as the force of gravity is relied upon for returning the lift cylinder to its retracted position during lowering of the conveyor 14. The valve V3, therefore, is a directional valve which bleeds the outflow fluid directly to the sump.

it will also be appreciated that whereas the passages and fluid lines which connect the valve V2 to the conveyor extension cylinder C1 have beeii legended with outflow and inflow designations, in reality these designations are applicable only to operation of the cylinder C1 for conveyor-extension purposes. For conveyorcontracting purposes, the outflow and inflow fluid lines are reversed.

Finally, it is to be noted that, whereas in FIG. 1 all of the various outlet openings 142 in the wall of the spool 30 are illustrated as being arranged in vertical alignment, in actual practice, these outlet openings will assume appropriate circumferential positions where they are conveniently accessible for short flexible hose connections to the hydraulic units or components which they serve.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, the disclosure of the present turntable assembly in association with a concretepouring truck is merely an exemplary environmental disclosure which requires that there be five fluid passages through the spool 32, in other installations involving the supporting of a greater or a lesser number of hydraulic units on the turntable platform 20, a corre sponding increase or reduction in the number of employed passages will be resorted to. Therefore, only insofar as the invention is particularly pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by letters patent is:

- 1. In a turntable assembly, a fixed imperforate base plate, a housing rotatably mounted on said base plate, a horizontal turntable platform supported by and rotatable in unison with said housing, a worm wheel secured to said housing in driving relationship and overlying said base plate in spaced parallelism, a plurality of traction rollers rotatably mounted on said base plate in circumferentially spaced underlying supporting relationship with respect to the peripheral edge of the worm wheel, said worm sheel being formed with a plurality of teeth on the periphery thereof, and a spring worm assembly mounted on said. base plate and disposed driving relationship with respect to said worm wheel, said spring worm assembly comprising a pair of spaced apart bearing supports secured to the base plate, a worm drive shaft rotatably mounted in said bearing supports, a resilient spring-like helix surrounding said drive shaft and disposed between said bearing supports, means fixedly securing the opposite end regions of said helix to the shaft in driven relationship, the inside diameter of said helix being greater than the diameter of said shaft whereby the medial region of the helix is free from the shaft, said medial region of the helix meshing with the peripheral teeth on the worm wheel in wormdriving relationship, a reversible driving motor mounted on said base plate, a flexible coupling operatively connecting said motor and drive shaft in driving relationship, and a continuous annular oil-retaining wall emcompassing the worm wheel, the worm helix, the traction rollers and the flexible coupling, said wall and base plate establishing a reservoir for a pool of lubricating oil within which the worm wheel, worm helix, traction rollers and flexible coupling are adapted to be at least partially submerged.

2. A turntable assembly as set forth in claim 1 and including, additionally, a plurality of additional traction rollers rotatably mounted on said base plate in circumferentially spaced relationship and overlying the peripheral edge of the worm wheel in stabilizing relationship, the height of said latter traction rollers above the base plate being less than the height of said oilretaining wall whereby such rollers are subject to lubrication by oil which is disposed within said reservoir. 

1. In a turntable assembly, a fixed imperforate base plate, a housing rotatably mounted on said base plate, a horizontal turntable platform supported by and rotatable in unison with said housing, a worm wheel secured to said housing in driving relationship and overlying said base plate in spaced parallelism, a plurality of traction rollers rotatably mounted on said base plate in circumferentially spaced underlying supporting relationship with respect to the peripheral edge of the worm wheel, said worm wheel being formed with a plurality of teeth on the periphery thereof, and a spring worm assembly mounted on said base plate and disposed in driving relationship with respect to said worm wheel, said spring worm assembly comprising a pair of spaced apart bearing supports secured to the base plate, a worm drive shaft rotatably mounted in said bearing supports, a resilient spring-like helix surrounding said drive shaft and disposed between said bearing supports, means fixedly securing the opposite end regions of said helix to the shaft in driven relationship, the inside diameter of said helix being greater than the diameter of said shaft whereby the medial region of the helix is free from the shaft, said medial region of the helix meshing with the peripheral teeth on the worm wheel in wormdriving relationship, a reversible drive motor mounted on said base plate, a flexible coupling operatively connecting said motor and drive shaft in driving relationship, and a continuous annular oil-retaining wall encompassing the worm wheel, the worm helix, the traction rollers and the flexible coupling, said wall and base plate establishing a reservoir for a pool of lubricating oil within which the worm wheel, worm helix, traction rollers and flexible coupling are adapted to be at least partially submerged.
 2. A turntable assembly as set forth in claim 1 and including, additionally, a plurality of additional traction rollers rotatably mounted on said base plate in circumferentially spaced relationship and overlying the peripheral edge of the worm wheel in stabilizing relationship, the height of said latter traction rollers above the base plate being less than the height of said oil-retaining wall whereby such rollers are subject to lubrication by oil which is disposed within said reservoir. 